A Muslim group and the French immigration minister have condemned a xenophobic graffiti attack on a mosque in the Caen suburb of Hérouville-Saint-Clair. Swastikas and anti-Islam messages including “Islam out of Europe” and “No Islam, no burqa” were sprayed on the mosque’s perimeter wall on the eve of Bastille Day.

Police have launched an investigation but admit that there is little evidence to help them identify the perpetrators.

The Conseil Français du Culte Musulman said it was “deeply shocked and angered” by the “completely incomprehensible” attack.

Immigration minister Eric Besson said: “The xenophobic messages sprayed on this mosque are not only evidence of an immense cowardice and stupidity, but they also suggest a desire to go against the founding values of our nation.

“France has always been, and must remain, a country of immigration and integration.”

In May, xenophobic and pro-Nazi graffiti was sprayed on the front window of a halal butcher’s shop in nearby Lisieux.

Some immigration experts and race relations groups have argued that the parliamentary debate on banning the burqa and a recent consultation on national identity have fuelled racism and prejudice in France.